No one publishes successful phishing and ransomware emails. Jon Thompson thinks he knows why.
The headlines say phishing scams are at an all-time high, and ransomware is growing exponentially, but conspicuous by their absence are examples of the emails behind successful attacks. It's becoming the cliché in the room, but there may be a reason: embarrassment.
Running an email honeypot network, you receive a flood of malicious email every day. Most is littered with glaring errors that point to lazy, inarticulate crooks trying to make the quickest buck from the least effort. When you do come across a rare, well though-out campaign, it shines like a jewel in a sea of criminal mediocrity.
To the average spammer, however, it's all just a numbers game. He cranks the handle on the botnet, so to speak, and money comes out.
This poses an important question: why, given the quality of most malicious spam, are new ransomware infections and high profile phishing attacks still making headlines almost every single day? Clearly, we're massively overestimating the amount of effort and intelligence invested by spammers.
With that in mind, what follows is a short list of 17 mistakes I routinely see, all of which immediately guarantee that an email is malicious. There are others, but these are the main ones. If this list reflects the mistakes found in the spam behind the headlines, then the size yet lack of sophistication of the problem should become apparent.
1. No Subject HeaderThis error is particularly prevalent in ransomware campaigns. Messages whose payloads have very low VirusTotal scores are being sent with no subject header. Maybe the sender thinks it'll pique the curiosity of the recipient, but it should also alert spam filters even before they examine the attachment.
2. No Set Dressing
3. Generic Companies
4. Multiple RecipientsThis is another example of laziness on the part of spammers. OK, they may have found an open relay to willingly spread messages rather than buy extra time on a botnet, but anything other than a one-to-one sender to recipient ratio should be an instant red flag.
5. Poor SalutationMuch apparently personalised spam doesn’t use a competent salutation, or uses a salutation that is simply the user name part of the email address (i.e.: "Dear fred.smith"). It would take effort to code a script that personalises the messages by stripping off the first name and capitalising the initial. Effort is the enemy of the fast buck.
6. No Body TextSending an email with a tantalizing subject header such as "Overdue – Please Respond!" but no body text explaining what or why it's overdue is as common in commodity ransomware as having no subject header. The attack again relies entirely on the natural curiosity of the recipient, who can and should simply ignore it. Spam filters should also take a keen interest.
7. Auto-translated Body Text
8. The Third PersonThis is a great example of a spam writer trying to distance himself from his crime. "PayPal has detected an anomaly in your account" and "they require you to log in to verify your account" just look weird in the context of a security challenge. This is supposed to be from PayPal, isn't it?
9. Finger Trouble
10. Unexpected Plurals and TensesUsing "informations" instead of "information" is a dead giveaway for spam and should be blocked when in combination with other indicators. Phrases such as "we detect a problem" instead of "we detected a problem" also stick out a mile.
11. Missing Definite ArticleMany spam emails stand out as somehow "wrong" because they miss out the definite article. One recent example I saw read: "Access is blocked because we detect credit card linked to your PayPal account has expired." An associated Yandex.ru return address gave the whole thing a distinct whiff of vodka.
12. The Wrong Word"Please review the document and revert back to us immediately". Revert? Really? Surely, you mean "get back", not "revert back". It may be difficult for spam filters to weed out this kind of error, but humans should spot it without difficulty.
13. Misplaced Emphasis
14. Tautological Terrors
What they really meant was: "To mark the release of our new software". The whole message was also riddled with the most outrageous auto-translate errors that it made difficult reading.